Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Reticulum [1] |
Right ascension | 04h 20m 47.046s [2] |
Declination | −59° 24′ 39.02″ [2] |
Apparent magnitude (V) | 9.36 [1] |
Characteristics | |
Spectral type | K2 V [3] |
U−B color index | +0.90 [4] |
B−V color index | +1.003±0.002 [1] |
Astrometry | |
Radial velocity (Rv) | 82.785±0.0008 [5] km/s |
Proper motion (μ) |
RA: 182.473±0.012
mas/
yr
[2] Dec.: 270.012±0.017 mas/ yr [2] |
Parallax (π) | 22.8888 ± 0.0121 mas [2] |
Distance | 142.50 ± 0.08
ly (43.69 ± 0.02 pc) |
Absolute magnitude (MV) | 6.225 [6] |
Details | |
Mass | 0.83±0.03 [7] M☉ |
Radius | 0.79±0.02 [7] R☉ |
Luminosity | 0.33±0.01 [7] L☉ |
Surface gravity (log g) | 4.56±0.03 [7] cgs |
Temperature | 4,923±32 [7] K |
Metallicity [Fe/H] | +0.30±0.07 [6] dex |
Rotation | 44 days [6] |
Rotational velocity (v sin i) | ≤ 1.5 [6] km/s |
Age | 7.7±2.3 [8] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 27894 is a single star with a system of orbiting exoplanets, located in the southern constellation of Reticulum. It is too faint to be seen with the naked eye at an apparent visual magnitude of 9.36. [1] This system lies at a distance of 142.5 light years from the Sun, as determined via parallax measurements, and is drifting further away with a radial velocity of 83 km/s. [5]
The spectrum of HD 27894 presents as a K-type main-sequence star, an orange dwarf, [6] with a stellar classification of K2 V. [3] This is a quiescent solar-type star that displays no significant magnetic activity in its chromosphere [9] and is spinning slowly with a rotation period of roughly 44 days. [6] The abundance of iron in the star is much higher than in the Sun, an indicator that it is metal-rich. [6] It has 83% of the mass of the Sun and 79% of the Sun's radius. The star is radiating 33% of the luminosity of the Sun from its photosphere at an effective temperature of 4,923 K. [7]
In 2005, the Geneva Extrasolar Planet Search Team announced the discovery of an extrasolar planet orbiting the star. [6] In 2017, the discovery of two additional exoplanets was announced. One is very close to the star like the one discovered earlier, while the other one orbits the star at a much larger distance. It is the first system where such a large gap between orbital distances has been found. [9] [10] In 2022, the inclination and true mass of HD 27894 d were measured via astrometry. The study only found strong evidence for planets b and d. [11]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥0.665+0.009 −0.007 MJ |
0.125±0.0001 | 18.02+0.01 −0.02 |
0.047+0.012 −0.008 |
— | — |
c | ≥0.162+0.011 −0.040 MJ |
0.198±0.001 | 36.07+0.26 −0.09 |
0.015+0.020 −0.002 |
— | — |
d | 6.493+0.987 −0.353 MJ |
5.362+0.206 −0.223 |
5019.5+32.6 −31.1 |
0.343+0.031 −0.026 |
101.524+14.742 −31.503 ° |
— |